u-boot/arch/x86/lib/early_cmos.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2017, Bin Meng <bmeng.cn@gmail.com>
*/
/*
* This library provides CMOS (inside RTC SRAM) access routines at a very
* early stage when driver model is not available yet. Only read access is
* provided. The 16-bit/32-bit read are compatible with driver model RTC
* uclass write ops, that data is stored in little-endian mode.
*/
#include <common.h>
#include <asm/early_cmos.h>
#include <asm/io.h>
u8 cmos_read8(u8 addr)
{
outb(addr, CMOS_IO_PORT);
return inb(CMOS_IO_PORT + 1);
}
u16 cmos_read16(u8 addr)
{
u16 value = 0;
u16 data;
int i;
for (i = 0; i < sizeof(value); i++) {
data = cmos_read8(addr + i);
value |= data << (i << 3);
}
return value;
}
u32 cmos_read32(u8 addr)
{
u32 value = 0;
u32 data;
int i;
for (i = 0; i < sizeof(value); i++) {
data = cmos_read8(addr + i);
value |= data << (i << 3);
}
return value;
}